1. Technical Field of the Invention
This invention relates to a battery charging device for controlling the charging of a battery which is a power source mounted in an electric vehicle, etc.
2. Discussion of the Prior Art
Conventionally, in charging a battery, a charging operation is vehicleried out until the battery is fully charged. In other words, the charging operation is continued until the SOC (state of charge) representing the amount of charge of a battery reaches about 100% to 103%. The fact that the charging operation is carried out until the battery is fully charged as was described above, is advantageous in that the amount of discharge current (the unit being Ah) of the battery can be sufficiently obtained.
If the battery has been charged fully, the sufficient discharge current of the battery can be obtained. However, the fact that the battery has been charged fully suffers from the following problems: That is, since the battery is charged over its capacity, during the final period of the charging operation, the charging power is liable to be wasted. For the same reason, the battery is liable to be deteriorated.
Furthermore, the charging period is long. Therefore, the battery may not be used when it is required to use it. More specifically, for instance, an electric vehicle or the like which is driven by the battery may not be used.